28V Linear Li+ Battery Charger with Smart Autoboot Assistant

Active: In Production.

The MAX8814 intelligent, stand-alone constant-current, constant-voltage (CCCV), thermally regulated linear charger is designed for charging a single-cell lithium-ion (Li+) battery. The MAX8814 integrates the current-sense circuit, MOSFET pass element, thermal-regulation circuitry, and eliminates the reverse-blocking Schottky diode to create the simplest and smallest charging solution for handheld equipment.

The IC controls the charging sequence from the prequalification state through constant-current fast-charge and the final constant voltage charge. Proprietary thermal-regulation circuitry limits the die temperature during fast-charging or when the IC is exposed to high ambient temperatures, allowing maximum charging current without damaging the IC.

The MAX8814 achieves high flexibility by providing an adjustable fast-charge current through an external resistor. Other features include an active-low control input (active-low EN) and an active-low input power-source detection output (active-low POK). The IC also features a booting assistant circuit that distinguishes input sources and battery connection and provides an output signal (ABO) for system booting.

The MAX8814 accepts an input supply range from 4.25V to 28V, but disables charging if the input voltage exceeds +7V to protect against unqualified or faulty AC adapters. The IC operates over the extended temperature range (-40°C to +85°C) and is available in a compact 8-pin thermally enhanced TDFN 2mm x 2mm package (0.8mm max height).

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